1. Field of the Invention
The present invention relates to a map data processing apparatus and a method thereof, for updating map data used by mobile units, e.g., a car navigation system, a portable telephone set, a personal digital assistant, and so on.
2. Description of Related Art
FIG. 42 is a constitutional view showing a conventional map data processing apparatus disclosed in, for example, Japanese Patent Application Laid-Open No. 11-95657. In the drawing, a reference numeral 1 denotes an information center for generating update information of map data; 2 denotes a transmitter for transmitting the update information generated by the information center 1; 3 denotes a receiver for receiving the update information; 13 denotes a map data storage device for storing the map data; 5 denotes a map data processor for specifying a part of the map data to be changed and a changing content in response to the update information received by the receiver 3, and then changing the map data; 6 denotes an input device; and 7 denotes an output device.
In FIGS. 43A to 43C, FIG. 43A is a view illustrating a road net before the updating of a certain area, which is represented by a node and a link; FIG. 43B is a view illustrating the road net after the updating of a certain area, which is represented by a node and a link; and FIG. 43C is a view illustrating a node number allocated to each node for making reference to the nodes of FIG. 43A and FIG. 43B.
Next, the operation will be described.
The information center 1 transmits update information used to update the map data of each area to a latest version through the transmitter 2. For example, when the road net is updated from FIG. 43A to FIG. 43B, the information center 1 transmits update information indicating that links between the nodes N2 and N5, and between the nodes N5 and N7 of the area have been deleted, a link has been added between nodes N3 and N6, and the nodes N5 and N7 have been deleted.
Upon having received the above-described update information through the receiver 3, the map data processor 5 takes out the map data of the road net FIG. 4A stored in the map data storage device 13, and executes updating for the map data based on the update information.
As a result, map data representing the road net (FIG. 43B) is constructed, and the map data of the road net (FIG. 43B) is stored in the map data storage device 13.
Because of the foregoing configuration of the conventional map data processing apparatus, as update information, information indicating the addition/deletion of nodes and links constituting the road net is used. However, the map data representing the road net is composed of not only data corresponding, one to one, to a node or a link, but also data indicating an adjacency relation between a node and a link, data indicating traffic regulation between links, and so on. Such data of various types are in close relation to one another. Accordingly, the map data processor 5 must calculate the type of data, a part to be changed, and a changing content from the addition/deletion information of the node or the link as update information. Therefore, a load placed on the map data processor 5 is excessively enlarged, which causes a drawback including the difficulty of performing quick updating, and so on.
In addition, there may be a case where the transmission of update information from the transmitter 2 to the receiver 3 is interrupted, making it impossible to receive the update information of a certain area. Because of the impossibility of updating the map data of the area, the map data of a latest version and the map data of an old version may be stored in a mixed manner in the map data storage device 13. In the map data representing the road net, the nodes are disposed in a predetermined order, and reference is made to a desired node by using its node number in the arraying order. However, as shown in FIG. 43C, node addition/deletion causes a change in the node numbers, and a different node number is allocated if a version is different though a similar node is used.
Each map data contains a node number for referring to the node of an adjacent area, i.e., an adjacent area node number, in order to show the connection of the road net between the adjoined areas. However, since the adjacent area node number indicates the node of the adjacent area of a version identical to that of the area concerned, if the version of the adjacent area is different from that of the area, the adjacent area node number indicates a different node, causing mismatching between the adjacent map data of different versions. As described above, there may be a case where the map data of different version are present in a mixed manner in the map data storage device 13. Therefore, mismatching occurred between the adjacent map data, which causes a drawback including the impossibility of processing map data, and so on.
The present invention was made to solve the foregoing problems, and objects of the invention are to provide an apparatus and a method for processing map data, capable of quickly updating the map data.
Other objects of the invention are to provide an apparatus and a method for processing map data, capable of preventing mismatching between the map data of different versions.
In accordance with an aspect of the invention, there is provided a map data processing apparatus, comprising: storing means for storing map data; information obtaining means for obtaining updating operation information indicating an updating content of the map data stored in the storing means; and updating means for updating the map data stored in the storing means according to the updating operation information obtained by the information obtaining means.
According to the map data processing apparatus of the invention, the information obtaining means obtains updating operation information containing updating position information, a part to be updated being represented by an offset from a predetermined reference position in the map data therein.
According to the map data processing apparatus of the invention, the information obtaining means obtains updating operation information containing, among data included in the map data, data specifying information for specifying data to be updated, and updating position information indicating a record having the data stored therein.
According to the map data processing apparatus of the invention, the information obtaining means obtains updating operation information containing updating position information indicating at least one or more updating positions in the record.
According to the map data processing apparatus of the invention, the information obtaining means obtains updating operation information containing update type information indicating update types of at least one or more parts to be updated in the record.
According to the map data processing apparatus of the invention, data storing means is provided for storing the updating operation information obtained by the information obtaining means when updating time by the updating means exceeds a predetermined reference time, and storing map data after updating by the updating means when the updating time is less than the predetermined time.
According to the map data processing apparatus of the invention, data storing means is provided for storing the updating operation information obtained by the information obtaining means when estimated updating time by the updating means exceeds a predetermined reference time, and storing map data after updating by the updating means when the estimated updating time is less than the predetermined reference time.
In accordance with another aspect of the invention, there is provided a map data processing apparatus, comprising: storing means for storing map data; information obtaining means for obtaining updating information the map data stored in the storing means; and updating means for updating the map data stored in the storing means according to the updating information obtained by the information obtaining means. In this case, the information obtaining means obtains corresponding node information indicating a correspondence between identical nodes of respective versions when the storing means stores map data, where a version of a certain area is different from that of the other area.
According to the map data processing apparatus of the invention, the information obtaining means obtains corresponding node information only when versions of areas adjacent to each other are different, the corresponding node information obtained regarding identical nodes present in the areas adjacent to each other.
According to the map data processing apparatus of the invention, the information obtaining means obtains only corresponding node information of the same node present in an overlapped part of the areas adjacent to each other.
In accordance with yet another aspect of the invention, there is provided a map data processing method, comprising the steps of: obtaining updating operation information indicating an updating content of stored map data; and updating the map data according to the obtained updating operation information.
According to the map data processing method of the invention, updating operation information is obtained, containing updating position information, a part to be updated being represented by an offset from a predetermined reference position in the map data therein.
According to the map data processing method of the invention, updating operation information is obtained, containing data specifying information for specifying data to be updated, and updating position information indicating a record having the data stored therein, among data included in the map data.
According to the map data processing method of the invention, updating operation information is obtained, containing updating position information indicating at least one or more updating positions in a record.
According to the map data processing method of the invention, updating operation information is obtained, containing update type information indicating update types of at least one or more parts to be updated in the record.
According to the map data processing method of the invention, the obtained updating operation information is stored when updating time of the map data exceeds a predetermined reference time, and the map data after updating is stored when the updating time is less than the predetermined reference time.
According to the map data processing method of the invention, the obtained updating operation information is stored when estimated updating time of the map data exceeds a predetermined reference time, and the map data after updating is stored when the estimated updating time is less than the predetermined reference time.
In accordance with a further aspect of the invention, there is provided a map data processing method, comprising the steps of: obtaining updating information of stored map data; and updating the map data according to the obtained updating information. In this case, if there is map data stored, where a version of a certain area is different from that of the other area, corresponding node information indicating a correspondence between identical nodes of the respective versions is obtained.
According to the map data processing method of the invention, corresponding node information is obtained only when versions of areas adjacent to each other are different, the corresponding node information obtained regarding identical nodes present in the areas adjacent to each other.
According to the map data processing apparatus of the invention, only corresponding node information of the same node present in an overlapped part of the areas adjacent to each other is obtained.